This is not an employment ad

This isn't an employment advertisement. We actually haven't gotten that far.
We a growing bicycle company in Miami, Fla. We have decent web site (www.jbimporters.com) that was contracted out through a guy who did it part time. This was three years ago.

He did a good job it seems, but we need someone in-house to address issues as they arise and expand the site's abilities. Ideally, we would hire someone to work on the front end of the site -- the appearance and navigation -- and then have someone else do the backside programming.

This ad would be for the later, but we really don't know what skill set is required to even place an ad.

If you were to do the backside programming of a site like ours, what programming knowledge would be required? We are open to someone coming in-house and re-doing the entire or going with the existing format.
So, what I'm asking is, how would you word the ad to make sure you got the right person?